Re-inforcement of Adriatic sturgeon in the Ticino River, Lombardy, Italy

Summary

The Adriatic sturgeon (Acipenser naccarii), Vulnerable and cut off from its Adriatic Sea spawning migration since a 1961 dam blocked the Po River, survives as a small landlocked freshwater population in Italy's Ticino River, protected since 1974 within Ticino Regional Park. Building on an earlier unsuccessful release of 250,000 juveniles since 1988 that produced no confirmed reproduction, a three-year EU LIFE project starting in 2003 combined habitat protection with a renewed captive breeding and release program: an initial stock of 1,152 sturgeon (1,011 juveniles and 41 adults, sourced from a fish farm's wild broodstock) was released between 2004 and 2006, with 31 adults and 10 juveniles surgically tagged for radio tracking, though seven died from tag-related infection or stress. From 2006, a dedicated captive breeding program using ten adults and 50 juveniles in a 300-meter semi-natural pool began producing offspring, with roughly 1,300 young released annually from 2007 through 2009. Post-release monitoring using 421 capture-recapture surveys found most juveniles dispersed downstream toward the Po confluence, informing a regional Action Plan that prioritized building two fish stairs (under construction, due 2010) to reconnect the river with the sea, alongside removal of over 5,600 predatory invasive sheat-fish since 2004. In 2009, 25 young sturgeon of about 3 cm were discovered near Pavia, confirming the first wild reproduction success in 20 years. Major difficulties included securing long-term funding, tracking tagged fish across a large river, and illegal underwater fishing targeting slow-maturing breeders. The project rates itself Highly Successful, citing confirmed wild reproduction and integration of the program into the park's permanent management.